The Belen area is uniquely situated along the Rio Grande rift; with the Basin and Range not far to the west and the Great Plains not far to the east, the geology here is diverse. The focus of this guidebook extends from Bernardo to Los Lunas and from the Manzano Mountains to the mesas west of the Rio Puerco. Many people travel this central New Mexico corridor along I-25, and this guidebook will provide a broad look at the geology in and around Belen. Topics include the southern Albuquerque Basin and the underlying structure relative to the Rio Grande rift flanks; tectonic events and metamorphic processes related to the Priest pluton emplacement in the Manzano Mountains; a late Paleozoic Lagerst√É¬§tten uncovered in Carrizo Arroyo in the western mesas; and the travertine rock record and its modern-day analog.